This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our lab has shown that red blood cells can produce alanine de novo with glucose providing the carbon backbone. However, at this time the source of nitrogen is unknown. We are running NMR-based metabolomics experiments to determine the source of nitrogen.